use GitHub API with Basic Auth over HTTPS
better net/http exceptions handling
use `warn` instead of `$stderr.puts`
test and document `hub browse` a single commit
`hub create <name>` to create GitHub repository with custom name

Closes #91
tired of duplicating examples between README & .ronn file
update history
teach `hub apply` about GitHub URLs, same as `hub am`
add documentation about `hub apply`
fix regex matching of SHAs in `cherry-pick`
use `echo` instead of commands callback procs
introduce `hub --noop` to output which commands would be run

The `--noop` argument has to appear before any git commands.

Closes #92
output few errors the proper way
ruby 1.8 compat
improve detecting whether we are currently in a git repo
silence $stderr when interrogating git
improve detecting upstream information
add preliminary `hub pullreq`
implement working `hub pull-request`
refactor and improve `pull-request`